SB_Maharana,
actually, its quite possible to build the way you are planning. Most of my build have fiberglass and CF rods (for strength) with biofoam for shape, thick medium/high density foam (for shock absorption).  As far as the weight is concerned, there are factors like wing loading to take care of, but on an average, a foamie with a weight of about 1 kg should be OK for a wingspan of 48-50inch. Beyond that the motor+battery combo becomes way too heavy/costly for a good flight time.

Thanks Panjkaj for this input. I am interested to make one rc plane, but don't know where to start and how to start.
Regarding the weight of the model, what should be the individual weight (say for a 48 inch wing span) of the wing, then weight of fuselage, and rest of the electronics. and what is the best material / wire for hot wire foam cutting. ( some say Piano wire etc.)  

Well, I use a pen knife most of the time for cutting biofoam. I have still not mastered the art of hotwire cutting. But since I work mostly with 5mm foam, its ok. The foam per se has very little weight, the main problem is in the choice of electrics involved as well as the reinforcements used. my 42inch pusher has an all up weight of 600gm with a 1000mAH lipo and a 48inch cub has about 900gm weight with a 1600mAH lipo.

How can I get one

can i buy from your website ,
will you be able to ship to hyderabad